1. Field of the Invention
The present invention relates to a refrigerator and a defrosting method thereof, and, more particularly, to a refrigerator and a defrosting method thereof which are capable of achieving an appropriate defrosting operation even when a part of constituent elements included in a defrosting system fails.
2. Description of the Related Art
Generally, in a refrigerator, lowering of a temperature around a heat exchanger is generated due to heat absorption caused by evaporation of a liquid-state refrigerant passing through the heat exchanger. When the temperature around the heat exchanger is lowered, moisture around the heat exchanger is cooled, so that frost accumulates on the surface of the heat exchanger. The accumulated frost should be removed because it may degrade the cooling efficiency of the heat exchanger.
In order to remove frost accumulated on such a heat exchanger, conventional refrigerators are provided with a defrost heater arranged around the heat exchanger, and adapted to generate heat, and a heat exchanger temperature sensor (or defrost sensor) adapted to measure a temperature of the heat exchanger.
In such a refrigerator, a defrosting mode is periodically carried out. When the defrosting mode is to be performed, the defrost heater is turned on to generate heat. The heat generation of the defrost heater is continued until a temperature sensed by the heat exchanger temperature sensor reaches a predetermined temperature. However, where the heat exchanger temperature sensor operates erroneously due to, for example, a failure thereof, it is impossible to appropriately determine the point of time at which the defrost heater is to be turned off. In this case, the defrosting mode is not carried out, in order to prevent overheat caused by an uncontrolled operation of the defrost heater.
However, the above mentioned conventional refrigerator takes a measure to stop driving of a compressor thereof when the heat exchanger temperature sensor, in addition to the measure to prevent the defrosting mode from being carried out. For this reason, there is a problem in that food stored in the refrigerator may go bad.